A six-bedroom penthouse at London's posh One Hyde Park development (picture) has just sold for a record-breaking £140 million, or about $220 million, making it the most expensive piece of residential real estate in the world in terms of current listings and sales.

The massive deal eclipses the paltry $150 million asking price for The Manor, Candy Spelling's monstrous mansion in Holmby Hills, California, previous holder of the World's Most Expensive title. While the identity of the buyer remains a closely-guarded secret, speculation is centering on oligarchs and oil sheikhs, the London Telegraph reports. The palatial penthouse stretches across two floors and boasts bullet-proof windows, a panic room and stunning views across the Serpentine lake in Hyde Park.

The residential owners will also have access to 24-hour room service from the neighboring Mandarin Oriental hotel, spas, squash courts a private wine-tasting facility and protection from security guards who are former members of the SAS, the UK's elite special forces unit.

One Hyde Park, which boasts 86 properties starting at around £20 million, is comprised of four hexagonal tower blocks due to be completed by December. Back in 2008 when the project was in its infancy my colleague Deirdre Woollard reported that Sheikh Hamad, the foreign minister of Qatar, had agreed to purchase an apartment there for a rumored £100 million, or around $196 million. More recently we revealed that British supercar maker McLaren will open a luxe new showroom in the development as well.